Air cargo rollout stop

ABSTRACT

A cargo rollout stop includes a base, and a guide head pivotally mounted to the base. The guide head is movable between a raised blocking position, and a lowered non-blocking position. A retraction pedal is pivotally mounted to the guide head, and is movable between a first position and a second position relative to the guide head. The retraction pedal permits downward rotation of the guide head from its raised blocking position to its lowered non-blocking position when the retraction pedal is in its second position, and blocks downward rotation of the guide head from its raised blocking position to its lowered non-blocking position when the retraction pedal is in its it first position.

FIELD OF THE INVENTION

The invention relates to aircraft cargo loading and unloading systems,and more particularly, relates to a rollout stop for selectivelypreventing unwanted movement of a cargo container or pallet in anaircraft.

BACKGROUND

A principle design goal associated with cargo aircraft is minimizing thetime required to load and unload cargo containers to and from anaircraft's cargo compartment. Aircraft cargo normally is pre-packaged inor on specially designed containers or pallets known as unit loaddevices (hereinafter “ULDs”) that are sized and shaped to occupysubstantially all available space within the cargo compartment of anaircraft. A modem aircraft's cargo compartment typically includes acargo deck equipped with a plurality of ball mats positioned proximateto the aircraft's cargo door. The ball mats facilitate rolling movementof the ULDs through the door and into and out of the cargo compartment.Aircraft cargo decks also typically include roller trays that extend infore and aft directions, and that facilitate rolling fore and aftmovement of ULDs between the area proximate to the cargo door andvarious cargo stowage positions within the cargo compartment. In manymodem cargo aircraft, ULDs can be loaded through the aircraft's nosesection and through at least one side cargo door.

During loading and unloading operations, an aircraft's cargo deck maynot be perfectly level, or can change from a level condition to anon-level condition as cargo is loaded or unloaded to and from theaircraft. In certain situations, an aircraft's cargo deck can slope in adirection that permits an unattended ULD to roll downhill toward theaircraft's open cargo door. In order to prevent an unattended ULD fromrolling out of a cargo compartment through an open cargo door, cargoaircraft often include one or more blocking devices (hereinafter“rollout stops”) that can be incrementally spaced along the sill of thecargo door. In operation, such rollout stop devices act like one-waygates that permit intended movement of a ULD through an open cargo doorand into an aircraft's cargo hold, and also prevent unintended rollingmovement of a ULD out of the aircraft's cargo door.

Various types of rollout stops are known for blocking unwanted outwardrolling movement of ULDs. Generally, such devices include at least oneretractable guide head that can be selectively raised to a height abovethe cargo deck that is sufficient to block outward rolling movement of aULD through a cargo door. Typically, such retractable guide heads have agenerally upwardly and inwardly sloping top surface that is contacted bythe leading lower edge and bottom surface of a ULD as the ULD passesover the stop and into a cargo hold, thereby forcing the upright guidehead to automatically retract as the ULD passes over the guide head andinto the cargo hold. Typically, the retractable guide heads are upwardlybiased by one or more springs that maintain the guide heads in a raisedposition until the guide heads are forced to retract by an inwardlymoving ULD. Once an inwardly moving ULD passes over the rollout stop,the springs return the guide heads to their raised positions, therebygenerally preventing the just-loaded ULD or another already-loaded ULDfrom rolling in a reverse direction through the open cargo door.Accordingly, such rollout stops can be described as being “over-ridable”in an inward direction, and as being generally “non-overridable” in anoutward direction. In order to permit ULDs to be unloaded from a cargocompartment without obstruction, the retractable guide heads generallyare configured to be selectively latched or otherwise restrained in alowered, non-blocking position when not in use.

Though prior art rollout stops can be effective to prevent outwardrolling movement of most ULDs, the lower edges of a ULD can becomewarped from use. In some cases, if a lower trailing edge of a ULD issufficiently upwardly bent, the lower trailing edge can be at anelevation that is sufficiently high to at least partially extend over araised guide head as the ULD approaches the rollout stop in an outwarddirection. Accordingly, the warped lower trailing edge and bottomsurface of the ULD may force the guide downward as the ULD passes overthe stop in an outward direction, thereby undesirably overriding therollout stop in the outward direction.

Another problem with prior art rollout stops is that they are notdesigned to yield to excessive contact loads with an outbound ULD. Insituations where an outbound ULD approaches a prior art rollout stop ata high velocity and/or is especially heavy, the outbound ULD can impactthe rollout stop with sufficiently high force to at least partiallydamage the aircraft structure to which the rollout stop is mounted.

Accordingly, there is a need for a rollout stop apparatus thatsubstantially reduces the possibility that an outbound ULD will overridethe rollout stop. Preferably, the rollout stop should be relativelysimple in construction such that production and repair costs areminimized. In addition, such a roll out stop should be designed to yieldto an outbound ULD that contacts the rollout stop with sufficient forceto otherwise damage the support structure of an aircraft to which therollout stop is mounted.

SUMMARY

In one embodiment, a cargo rollout stop includes a base, and a guidehead pivotally mounted to the base. The guide head is movable between araised blocking position, and a lowered non-blocking position. Aretraction pedal is pivotally mounted to the guide head, and is movablebetween a first position and a second position relative to the guidehead. The retraction pedal permits downward rotation of the guide headfrom its raised blocking position to its lowered non-blocking positionwhen the retraction pedal is in its second position, and blocks downwardrotation of the guide head from its raised blocking position to itslowered non-blocking position when the retraction pedal is in its itfirst position.

In one embodiment, a cargo rollout stop for an aircraft includes a meansfor stopping. The means for stopping is movable between a stoppingposition and an inactive position. The rollout stop further includes ameans for supporting the means for stopping. The means for supporting isselectively movable between a support position and a retracted position.When the means for supporting is in its support position, the means forstopping is prevented from moving from its stopping position and itsinactive position. When the means for supporting is in its retractedposition, the means for stopping is free to move from its stoppingposition to its inactive position.

A method of selectively preventing a cargo container or pallet fromrolling out of a cargo door of an aircraft includes providing at leastone selectively retractable guide head proximate to a cargo deck andadjacent to the cargo door. The method further includes raising theguide head to a cargo stopping position, and blocking retraction of theguide head away from its cargo stopping position due to contact betweenthe guide head and an outwardly moving cargo container. The method alsoincludes permitting retraction of the guide head away from its cargostopping position as the result of contact between the guide head and aninwardly moving cargo container.

An apparatus for selectively preventing retraction of a retractableguide head of a cargo rollout stop includes a retraction pedal that ispivotally mounted to the guide head. The pedal upwardly extends from acam surface of the guide head when the retraction pedal is in a raisedposition. A blocking member downwardly depends from the retraction pedalwhen the retraction pedal is in its raised position, and blocks downwardmovement of the guide head when the retraction pedal is in the raisedposition.

These and other aspects of the invention will be apparent from a readingof the following detailed description together with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top outboard perspective view of one embodiment of a rolloutstop according to the invention in a raised, blocking position.

FIG. 2 is a top outboard perspective view of the rollout stop of FIG. 1in a retracted, non-blocking position.

FIG. 3 is a top inboard view of the rollout stop of FIGS. 1 and 2 in araised, blocking position.

FIG. 4 is a top inboard view of the rollout stop of FIGS. 1-3 in aretracted, non-blocking position.

FIG. 5 is a side elevation view of the rollout stop of FIGS. 1-4 in araised, blocking position.

FIG. 6 is a side elevation view of the rollout stop of FIGS. 1-5 in aretracted, non-blocking position.

FIG. 7 is a bottom inboard perspective view of the rollout stop of FIGS.1-6.

FIG. 8 is a top outboard perspective view of a base portion of therollout stop shown in FIGS. 1-7.

FIG. 9 is a top outboard view of a guide head portion of the rolloutstop shown in FIGS. 1-7.

FIG. 10 is a top outboard view of a guide head portion of the rolloutstop shown in FIGS. 1-7.

FIG. 11A is a cross sectional view of a portion of the rollout stopshown in FIGS. 1-7 taken along line 11A-11A in FIG. 1.

FIG. 11B is a cross sectional view of the portion of the rollout stopshown in FIG. 11A with the shear pin sheared and the guide head rotatedupward beyond its normal erect position.

FIG. 12 is a side elevation view of the rollout stop shown in FIGS. 1-7with the guide head being contacted by an upwardly deformed leading edgean outbound ULD.

FIG. 13 is a cross-sectional elevation view of the rollout stop shown inFIGS. 1-7 showing the pedal and guide head in there raised positions.

DETAILED DESCRIPTION

One embodiment of a rollout stop according to the invention is shown inFIGS. 1-7. As shown in FIGS. 1-4, a rollout stop 110 can include a base120, a guide head 130 movably mounted to the base 120, and a blockingmember or retraction pedal 150 movably mounted to the guide head 130.The guide head 130 and the retraction pedal 150 are shown in their fullyraised positions in FIGS. 1, 3, and 5, and are shown in their fullylowered or retracted positions in FIGS. 2, 4, and 6.

Referring to FIG. 1, the guide head 130 can be pivotally mounted to thebase 120 by a hinge pin 139. As shown in FIGS. 1 and 2, springs 143 canbe arranged to push the guide head 130 upward and away from the base 120toward its raised position. As best seen in FIGS. 1, 2 and 11A, theupward rotational displacement of the guide head 130 can be limited bycontact between a pair of arms 131 on the guide head 130, and a pair ofshear pins 141 positioned below the hinge pin 139 on the base 120.

As shown in FIGS. 3-5, the guide head 130 can include a substantiallyplanar blocking surface 135 and an upper cam surface 137. The blockingsurface 135 can be substantially vertical when the guide head 130 is inits raised position. The upper cam surface 137 of the guide head 130 canhave various profiles, including being substantially planar or having aconcave curvature. In the embodiment shown in FIGS. 5 and 6, the uppercam surface 137 has a slightly concave curvature.

As shown in FIGS. 1-6, the retraction pedal 150 can be pivotally mountedto the guide head 130 such that the pedal 150 can rotate between araised position (shown in FIGS. 1, 3 and 5), and a retracted position(shown in FIGS. 2, 4 and 6). The retraction pedal 150 is received in apedal opening 133 in the guide head 130 which is shown in FIG. 9. Thepedal opening 133 is configured to permit rotating movement of the pedal150 in the opening 133, and to permit portions of the pedal 150 toupwardly and downwardly extend from the opening. As shown in FIG. 5, theretraction pedal 150 can be pivotally mounted to the guide head 130 by apivot pin 173 engaged in a pivot opening 151 in the retraction pedal 150(as shown in FIG. 10), and aligned openings 137 in the guide head 130(as shown in FIG. 9). As shown in FIG. 13, one or more springs 301 canbe provided between the guide head 130 and pedal 150 to resiliently biasthe retraction pedal 10 toward its raised position. As shown in FIGS. 1,2, 4, 5 and 10, the retraction pedal 150 can include an upper pedalsurface 157. As best seen in FIGS. 5 and 10, the upper pedal surface 157can have a slightly convex curvature. The convex curvature facilitatesdownward movement of the pedal 150 as a leading lower edge of an inboundULD contacts and traverses the upper pedal surface 157. Alternatively,the upper pedal surface 157 can be substantially flat.

As shown in FIG. 10, the retraction pedal 150 can include a blockingportion 153 that downwardly extends from the retraction pedal 150 whenthe pedal 150 is in its raised position. As shown in FIGS. 3 and 13, thedownwardly depending blocking portion 153 of the pedal 150 contacts thebase 120 when the pedal 150 is in its raised position. As also shown inFIGS. 3 and 13, the base 120 can include a support block 122 thatunderlies and vertically supports the blocking portion 153 of the pedal150 when the pedal 150 and guide head 130 are in their raised positions.Accordingly, contact between the blocking portion 153 of the pedal 150and the base 120 blocks downward movement of the pedal 150 and theconnected guide head 130 from their raised positions.

As shown in FIG. 7, the bottom of the base 120 can include asubstantially planar lower surface 126, a pair of downwardly dependingfeet 127, and an elongated series of spaced lobes 129. The feet 127 andspaced lobes 129 can be of a type known in the art for mounting items toconventional seat tracks in an aircraft. The feet 127 and lobes 129 canbe substantially circular in shape, and configured to be insertedthrough the spaced circular openings of a pair of conventional parallelaircraft seat tracks (not shown in the drawings). Once so inserted, thefeet 127 and lobes 129 are configured to longitudinally slide in thebell-shaped grooves of the conventional seat tracks until the base 120is in a desired installed position, and the feet 127 and lobes 129 arealigned beneath vertical restraining tabs of the seat tracks. As shownin FIG. 7, the base 120 can further include a pair of anchor openings164 that align with anchor bolts 62 and anchor buttons 164 of typesknown in the art that are configured to anchor the base 120 toconventional seat tracks along the sill of an aircraft cargo door.

The upper cam surface 137 of the guide head 150 and the upper pedalsurface 157 of the retraction pedal 150 can be configured such that asthe lower leading edge of an inbound ULD reaches the rollout stop 110and begins to pass over the stop 110, contact between the lower leadingedge of the ULD and the pedal surface 157 and upper cam surface 137downwardly rotates the retraction pedal 150 such that blocking contactbetween the blocking portion 153 and the base 120 (as shown in FIG. 13)is disrupted. Accordingly, as the inbound ULD continues to pass over theguide head 130, the guide head 130 and retraction pedal 150 downwardlydeflect beneath the lower leading edge of the ULD. Accordingly, aninbound ULD automatically overrides the rollout stop 110, and is free topass over the stop 110 without substantial obstruction during cargoloading.

Once the inbound ULD completely passes over the stop 110, the springs143 automatically return the retraction pedal guide head 130 to itsraised position. As shown in FIG. 5, when the guide head 130 is in itsraised position, a substantial portion of the guide head 130 extendsabove the cargo roller plane “C” on which the bottoms of the ULDstravel. Accordingly, the substantially vertical blocking surface 135 ofthe raised guide head 130 blocks passage of an outbound ULD 100 that mayinadvertently move in an outbound direction as indicated by the arrow inFIG. 5. In addition, the downwardly depending blocking portion 153 ofthe raised pedal 150 (as shown in FIG. 13) effectively blocks downwardmovement of the guide head 130 that might otherwise be caused by adownward force F (as shown in FIG. 12) that might result from contactbetween the top edge of the guide head 130 and an upwardly deformed orotherwise upwardly positioned lower edge of an outbound ULD 100.Accordingly, though an inbound ULD can override the upright rollout stop110 when traveling in an inbound or loading direction as describedabove, the stop 110 effectively prevents an outbound ULD 100 frominadvertently overriding the rollout stop 110 when moving in theoutbound or exit direction.

As shown in FIG. 6, during unloading operations, it is necessary toretract the guide head 130 from its raised position in order to permitan outbound ULD 100 to pass over the rollout stop 110 withoutobstruction as the ULD 100 exits the cargo hold. The retracted guidehead 130 also permits an inbound ULD 102 to pass over the rollout stop110 without obstruction as the ULD 102 enters the cargo hold. In orderto restrain the guide head 130 in the retracted position shown in FIG.6, the rollout stop 110 includes a latching mechanism 170 thatselectively engages and restrains the retraction guide head 130 when theguide head 130 is rotated to its lowermost, retracted position. As shownin FIG. 6, the latch mechanism 170 can include a button 174 engaged witha spring-loaded latch pin 172. To retract the erected rollout stop 110shown in FIGS. 1, 3, and 5, a cargo crew person can step on and depressthe pedal surface 157 of the retraction pedal 150 to force the pedal 150and the interconnected guide head 130 down to their lowered positions.As a result, the pedal 150 is forced to rotate downwardly about pivotpin 173, and the guide head 130 is forced to rotate downwardly about itshinge pin 139. Once the retraction guide head 130 is fully lowered asshown in FIG. 6, the latch pin 172 snaps into restraining engagementwith the guide head 130, thereby preventing the wound springs 143 (shownin FIGS. 1 and 2) from pushing the guide head 130 back to an erectposition. In order to raise the retracted and latched guide head 130 toits raised, blocking position, a crew person can depress the latchbutton 174, thereby disengaging the latch pin 172 from the guide head130, and permitting the springs 143 to automatically return the guidehead 130 to its erect, cargo-blocking position (shown in FIGS. 1, 3 and5). The latch pin 172 can be actuated by any type of latching mechanism170 that permits selective, manually-actuated displacement of the latchpin 172 between engagement and disengagement with the guide head 130.

As shown in FIGS. 11A and 11B, one embodiment of a rollout stopaccording to the invention can include one or more shear pins 141. Inthe embodiment shown in FIGS. 11A and 11B, a shear pin 141 is supportedon a pivot support 125 on the base 120, or is disposed between a pair ofadjacent pivot supports 125 on the base. As shown in FIG. 11A, when theguide head 130 is in its normal upright stopping position, the shear pin141 blocks further upward rotation of the guide head 130 due to contactbetween the shear pin 141 and the arm 131 on the guide head 130. Theshear pin 141 can be designed such that the pin 141 has sufficient shearstrength to block further rotation of the guide head 130 and arm 131under normal ULD contact loads. The shear pin 141 also is designed suchthat the pin 141 will be sheared by the guide head arm 131 when theloads exceed a predetermined maximum safe load condition, therebypermitting outward rotation the guide head 130 as shown in FIG. 11B. Theguide head 130 can be configured such that once the shear pins 141 havebeen sheared away by the guide head arms 131. The guide head is free torotate about 180 degrees from its retracted position. In a preferredembodiment, the shear pins 141 can be designed to shear when a maximumload of about 10,000 pounds is applied to the blocking surface 135 ofthe guide head 130 in an outbound direction. As shown in FIGS. 1 and 2,the rollout stop 110 can include two shear pins 141, and two or morecorresponding guide head arms 131. In other embodiments, the rolloutstop 110 can include multiple shear pins and/or guide head arms at eachend of the rollout stop.

Thus, the rollout stop 110 described above provides an apparatus havinga relatively simple construction that can substantially reduce thepossibility that an outbound ULD 100 might override the rollout stop110. The rollout stop 110 described above also is designed to yield toexcessive ULD impact loads in order to minimize the possibility ofdamage to an aircraft structure.

The above description of various embodiments of the invention areintended to illustrate various benefits, features and aspects of theinvention. Persons of ordinary skill in the art will recognize thatcertain changes and modifications can be made to the describedembodiments without departing from the invention. For example, thoughthe guide head and retraction pedal are shown and described as beingpivotally mounted to a base, the pedal and/or guide head can beotherwise movably mounted to a base in any manner that facilitatesupward and downward movement. For example, the retraction pedal and/orguide head can be attached to the base by a linkage system, such as afour-bar linkage system. All such changes and modifications are intendedto be within the scope of the appended claims.

1. A cargo rollout stop comprising: (a) a base; (b) a guide head movablymounted to the base, the guide head being movable between a raisedblocking position and a lowered non-blocking position; (c) a blockingmember movably mounted to the guide head, the blocking member beingmovable between a first position and a second position relative to theguide head; and (d) at least one shear pin that is positioned to blockupward movement of the guide head beyond its raised blocking positionunder a first operating load, and is configured to permit upwardmovement of the guide head beyond its raised blocking position under asecond operating load that is higher than the first operating load; (e)wherein the blocking member permits downward rotation of the guide headfrom its raised blocking position to its lowered non-blocking positionwhen the blocking member is in its second position, and blocks downwardrotation of the guide head from its raised blocking position to itslowered non-blocking position when the blocking member is in its itfirst position.
 2. A cargo rollout stop according to claim 1, whereinthe blocking member includes a pedal portion that is operative toselectively move the blocking member from its first position to itssecond position.
 3. A cargo rollout stop according to claim 1, whereinthe guide head includes an upper cam surface, the cam surface beingconfigured to engage a leading edge of an inbound cargo unit such thatthe guide head is moved from its raised blocking position to its lowerednon-blocking position by inbound movement of the leading edge.
 4. Acargo rollout stop according to claim 2, wherein the pedal portionincludes an upper surface configured to engage a leading edge of aninbound cargo unit such that the blocking member is moved from its firstposition to its second position by inbound movement of the leading edge.5. A cargo rollout stop according to claim 1, further comprising atleast one spring that is operable to bias the guide head toward itsraised blocking position.
 6. A cargo rollout stop according to claim 1,further comprising at least one spring configured to urge the blockingmember toward its first position relative to the guide head.
 7. A cargorollout stop according to claim 1, further comprising a latch mechanismoperable to restrain the guide head in a retracted position.
 8. A cargorollout stop according to claim 1, further comprising at least onemounting member configured for connection to a seat track of anaircraft.
 9. (canceled)
 10. A cargo rollout stop according to claim 1wherein the guide head is pivotally mounted to the base. 11-20.(canceled)
 21. An aircraft cargo rollout stop comprising: (a) a baseconfigured for selective removable attachment to an aircraft cargo deckproximate to an aircraft cargo door; (b) a guide head pivotally mountedto the base, the guide head being movable between a raised blockingposition and a lowered non-blocking position; (c) a blocking memberpivotally mounted to the guide head, the blocking member including apedal portion and an opposed blocking portion having an unrestraineddistal end, and being movable between a stowed position and a supportposition relative to the guide head, the pedal portion being operable tofree the guide head for movement from its support position to its stowedposition; and (d) at least one spring operable to bias the guide headtoward the raised blocking position; (e) wherein the blocking memberpermits downward rotation of the guide head from its raised blockingposition to its lowered non-blocking position when the blocking memberis in its stowed position, and wherein the blocking portion downwardlyextends from the guide head and the distal end seats against the basewhen the blocking member is in the support position, thereby blockingdownward rotation of the guide head from its raised blocking position toits lowered non-blocking position; and (f) wherein the guide head isconfigured to substantially block movement of a cargo container throughthe cargo door when the guide head is in its raised blocking position.22. An aircraft cargo rollout stop according to claim 21, wherein theguide head includes an upper cam surface, the cam surface beingconfigured to engage a leading edge of an inbound cargo container suchthat the guide head is urged from its raised blocking position to itslowered non-blocking position by inbound movement of the leading edge.23. An aircraft cargo rollout stop according to claim 21, wherein thepedal portion includes an upper surface configured to engage a leadingedge of an inbound cargo unit such that the blocking member is movedfrom its support position to its stowed position by inbound movement ofthe leading edge.
 24. An aircraft cargo rollout stop according to claim21, further comprising at least one spring operable to bias the blockingmember toward its support position.
 25. An aircraft cargo rollout stopaccording to claim 21, further comprising a latching mechanism operableto restrain the guide head in the lowered non-blocking position.
 26. Anaircraft cargo rollout stop according to claim 21, wherein the basecomprises at least one mounting member configured for selectiveremovable attachment to a seat track of an aircraft.
 27. An aircraftcargo rollout stop according to claim 21, further comprising at leastone shear pin positioned to block upward movement of the guide headbeyond its raised blocking position under a first operating load, andbeing configured to permit upward movement of the guide head beyond itsraised blocking position under a second operating load that is higherthan the first operating load.
 28. An aircraft cargo rollout stop forselectively blocking cargo containers against exiting an aircraft cargodoor, the aircraft cargo rollout stop comprising: (a) a base configuredfor removable attachment to an aircraft seat track proximate to anaircraft cargo door; (b) a guide head pivotally mounted to the base, theguide head being movable between a raised blocking position and alowered non-blocking position, and including a pedal recess therein; (c)a pedal member including a pedal portion and a blocking portion, thepedal member being pivotally connected to the guide head, wherein thepedal portion upwardly extends from the pedal recess of the guide headwhen the guide head is in the raised blocking position, and the pedalportion is substantially recessed within the pedal recess when the guidehead is in the lowered non-blocking position; and (d) at least onebiasing member configured to urge the guide head toward its raisedblocking position; (e) wherein the blocking portion of the pedal memberis configured to block downward rotation of the guide head from itsraised blocking position to its lowered non-blocking position when thepedal portion upwardly extends from the guide head; and (f) wherein theguide head is configured to substantially block exiting movement of acargo container through the cargo door when the guide head is in itsraised blocking position.
 29. An aircraft cargo rollout stop accordingto claim 28, wherein the guide head includes an upper cam surface, thecam surface being configured to engage a leading edge of an inboundcargo container such that the guide head is urged from its raisedblocking position to its lowered non-blocking position by inboundmovement of the leading edge.
 30. An aircraft cargo rollout stopaccording to claim 28, wherein the pedal portion includes an uppersurface configured to engage a leading edge of an inbound cargo unitsuch that the blocking member is urged from its support position to itsstowed position by inbound movement of the leading edge.
 31. An aircraftcargo rollout stop according to claim 28, further comprising a latchingmechanism operable to releasably restrain the guide head in the lowerednon-blocking position.